1. Field of the Invention
The present invention relates to an electronic apparatus that has a plurality of card receptacles in which PC cards for wireless communications are received.
2. Description of the Related Art
An electronic apparatus, such as a portable computer and a server used for the management of a large amount of data, comprises a plurality of card receptacles in which PC cards that conforms to the specifications determined by the PCMCIA (Personal Computer Memory Card International Association) are received.
The card receptacles are provided inside the housing of the electronic apparatus and are stacked in the thickness direction of that housing, as in the apparatus shown in Jpn. Pat. Appln. KOKAI Publication No. 11-167428. The card receptacles comprise card slots through which PC cards are inserted or removed. The card slots are open in a peripheral surface of the housing. Where a plurality of PC cards are connected to the electronic apparatus, they are inserted into the card receptacles in parallel to one another and face one another.
In recent years, more and more wireless LANs use broadband technology, and wireless communications devices have become low in price. As a result of these, environments for short-distance wireless communications are now in place. Under the circumstances, PC cards having the communications function are provided for a plurality of electronic apparatuses, so as to connect them through a wireless LAN.
A PC card for wireless communications comprises: a card main body containing a wireless interface circuit; and an antenna section containing an antenna element. The antenna section is located at one end of the card main body and is outside the housing when it is inserted into the card receptacle through the card slot. With this structure, the antenna section is not surrounded by any object that would have negative effects on radiation field. In other words, the antenna section can be viewed from any position outside the housing.
The antenna section of the PC card is thicker than the card main body. If the wireless-communications PC card provided with the antenna section is inserted into a lower card receptacle, the antenna section is inevitably located in the card slot of the upper card receptacle. In this case, another PC card cannot be inserted into the upper card receptacle because the antenna section of the PC card inserted in the lower card receptacle becomes an obstacle. In other words, PC cards cannot be inserted to all of the card receptacles.
To solve the problem described above, it may be thought to increase the intervals between the card receptacles. However, since the card receptacles are stacked in the thickness direction of the housing, an increase in the intervals between the card receptacles inevitably results in an increase in the thickness of the housing. This becomes a bard to the recent trend of providing thin electronic apparatuses.
Where two PC cards for wireless communications are parallel to each other, their antenna sections inevitably overlap each other. As a result, the electric fields the antenna sections emit radially interfere with each other, resulting in poor wireless performance.